# VM

The VM function computes the magnitude of the total relative translational velocity between markers I and J. Time derivatives are calculated in the reference frame of marker L. The first argument, marker I, must be specified. The second and third arguments are optional.

VM(I, J, L)

## Arguments

I
The marker whose velocity is to be computed.
J
The marker with respect to which the velocity is to be computed. If omitted, it defaults to the ground coordinate system.
L
Time derivatives are taken in the coordinate system of this marker. If omitted, it defaults to the ground coordinate system.

## Example

<Post_Request
comment             = "VM Example"
id                  = "70000045"
type                = "EXPRESSION"
expr2               = "VM(30301010,30301011,30301011)"
/>